Orthopyxis asymmetrica Stechow, 1919

Gravili, Cinzia, Vito, Doris De, Camillo, Cristina Gioia Di, Martell, Luis, Piraino, Stefano & Boero, Ferdinando, 2015, The non-Siphonophoran Hydrozoa (Cnidaria) of Salento, Italy with notes on their life-cycles: an illustrated guide, Zootaxa 3908 (1), pp. 1-187 : 157-158

Orthopyxis asymmetrica Stechow, 1919

Fig. 111

See Peña Cantero & Carrascosa (2002) for a complete synonymy.

Material examined. HCUS-S 118 (Hydrozoa Collection, University of Salento—fauna of the Salento Peninsula).

Description (based on our own observations; Piraino & Morri 1990; Peña Cantero & Carrascosa 2002):

Hydroid. Hydrorhiza as creeping stolon system; colonies stolonal; hydranth pedicels twisted spirally over their whole length and bearing a single distal hydrotheca with a large and slightly asymmetrical basal spherule; basal chamber and hydrotheca with strongly asymmetrical perisarc thickening maximal at base and smoothly decreasing towards aperture. Gonothecae: female gonophores on the hydrorhiza bellshaped, laterally flattened, with short annulated pedicels and orange-coloured eumedusoids with 4 radial canals, and 4–8 interradial statocysts.

Habitat type and substrate. Littoral species reported from near the tidal level to 25 m depth (García Carrascosa 1981; Gili 1986) on leaves of Posidonia oceanica .

Cnidome. Microbasic mastigophores.

Seasonality. In the Mediterranean Sea colonies occur in February, July ( García-Rubies 1987 as Campanularia asymmetrica ), March, April (De Vito 2006; this study), May ( Piraino & Morri 1990), and September ( Giovannetti et al. 2010).

Reproductive period. May ( Piraino & Morri 1990) in the Tyrrhenian Sea.

Distribution. Mediterranean endemic ( Medel & López-González 1996; Bouillon et al. 2004; Gravili et al. 2008a; Soto Ãngel & Peña Cantero 2013).

Records in Salento. Rare at Otranto (De Vito 2006; Gravili 2006; Gravili et al. 2008a; this study), and Porto Cesareo ( Andreano 2007).

Remarks. Cornelius (1982) considered Campanularia asymmetrica as conspecific with Orthopyxis integra . Moreover, Östman et al. (1987) did not find distinct differences in the cnidome of both species. Nevertheless, Peña Cantero & García Carrascosa (2002) and many authors studying Mediterranean material keep the two species distinct.

References. Picard (1952, 1958a), Relini et al. (1977), Repetto et al. (1977), Boero (1981a, b), Fresi et al. (1982), Boero et al. (1985) all as Campanularia asymmetrica ; Gili (1986), Garcia Rubies (1987, 1992), Roca (1987), Piraino & Morri (1990), Hughes et al. (1991), Medel & López-González (1996), Piraino et al. (1999), Bouillon et al. (2004), De Vito (2006), Gravili (2006), Gravili et al. (2008a), Giovannetti et al. (2010).

Figures

FIGURE 111. Orthopyxis asymmetrica: hydroid (drawn by F. Boero). Scale bar: 250 µm.